When elimination diets go wrong

Consumers are being warned about unnecessarily cutting foods from diets, after a four-year-old boy suffered an anaphylactic reaction despite previously testing negative to food allergies.

The New Zealand boy was rushed to hospital suffering hives, facial swelling, throat tightness and stridor after swallowing three spoonfuls of yoghurt.

He'd been on a heavily restricted diet, despite having had a skin-prick test that showed negative to food allergies including soybean and cow's milk.

Experts say the case highlights the risk of anaphylaxis from loss of oral tolerance, a consequence of unnecessary food exclusions.

Pediatricians from Waitakere Hospital in New Zealand reported on the case for The Australasian Journal of Dermatology, saying: "Prolonged dietary elimination can potentially induce a loss of oral tolerance leading to anaphylactic reactions on the intentional or accidental reintroduction of such food."

The boy's family was concerned that certain food groups might have been contributing to his eczema, and eliminated foods including dairy products, wheat, soy, egg, chicken, fish, lentils and nuts.

The authors say that while food allergies and eczema are common, dietary elimination is required only to manage confirmed food allergies.